<!DOCTYPE HTML>
<html>
    <head>
        <meta http-equiv="content-type" content="text/html; charset=UTF-8" />
    </head>
    <style>
        body {
            background-color: #ccc;
        }
    </style>
<body>

<canvas id="clock" width="400" height="400" style="border:1px solid #ccc;margin:100px auto;display:block;"></canvas>

<script src="./clock.js"></script>
</body>
</html>